ABSTRACT
Wind is one of the fastest growing renewable energy resources today, and the most efficient way to harvest wind energy is to use wind turbines. Modern wind turbines can be categorised mainly as horizontal axis wind turbines (HAWTs) rotating around a horizontal axis and vertical axis wind turbines (VAWTs) spinning around a vertical axis. VAWTs offer a number of advantages over modern HAWTs, but one of the major challenges facing VAWTs is their lower power efficiency, as the angles of attack (AOAs) of the blades vary rapidly in one revolution. Extensive research is therefore being carried out on the pitch control of the blades of a VAWT. Since VAWTs are getting bigger to generate more power, structural health monitoring (SHM) will be applied to large wind turbines to ensure their functionality, safety and integrity. This chapter focuses on VAWTs with particular interest in attempting to establish a smart VAWT through the synthesis of energy harvesting, pitch control and SHM functions. The current research status on energy harvesting of VAWTs is considered first in this chapter. The research on the control of the blade pitch angles of a VAWT for the improvement of its power efficiency, startup capability and shut-down performance is then introduced. Based on wind load simulation as well as the fatigue and ultimate strength analyses of laminated composite blades and other structural members in a VAWT, the SHM system is proposed for the VAWT. The concept of a smart VAWT comprising energy harvesting, pitch control and SHM functions is finally presented in the last part of this chapter.
