Blade Design Optimisation for Fixed-Pitch Fixed-Speed Wind Turbines

Lin Wang,Xiongwei Liu,Xinzi Tang

doi:10.5402/2012/682859

Abstract

Fixed-pitch fixed-speed (FPFS) wind turbines have some distinct advantages over other topologies for small wind turbines, particularly for low wind speed sites. The blade design of FPFS wind turbines is fundamentally different to fixed-pitch variable-speed wind turbine blade design. Theoretically, it is difficult to obtain a global mathematical solution for the blade design optimisation. Through case studies of a given baseline wind turbine and its blade airfoil, this paper aims to demonstrate a practical method for optimum blade design of FPFS small wind turbines. The optimum blade design is based on the aerodynamic characteristics of the airfoil, that is, the lift and drag coefficients, and the annual mean wind speed. The design parameters for the blade optimisation include design wind speed, design tip speed ratio, and design attack angle. A series of design case studies using various design parameters are investigated for the wind turbine blade design. The design outcomes are analyzed and compared to each other against power performance of the rotor and annual energy production. The design outcomes from the limited design cases demonstrate clearly which blade design provides the best performance. This approach can be used for any practice of FPFS wind turbine blade design and refurbishment.

Highlights

Wind energy has been receiving more and more attention as one of the most viable renewable energy sources
Due to the nature of fixed-speed control, a fixed-pitch fixed-speed (FPFS) wind turbine uses asynchronous or induction generator with gearbox connected to the rotor, and the generator can be directly tied to the grid [2]
ISRN Renewable Energy and Kulkarni’s research work demonstrated that with high values of Weibulls shape parameter, FPFS wind turbines are fairly competitive in terms of annual energy production (AEP), which is about 88% of its variable-speed version [6]

Summary

Introduction

Wind energy has been receiving more and more attention as one of the most viable renewable energy sources. Wind turbine technologies have been developed to achieve better performance for harvesting the energy in the wind in the last two decades. One of the major R&D areas for wind turbine technology development is blade design optimisation [1]. For fixed-pitch wind turbines, there are two different rotor speed control strategies, that is, fixed speed and variable speed [2, 3]. Due to the nature of fixed-speed control, a fixed-pitch fixed-speed (FPFS) wind turbine uses asynchronous or induction generator with gearbox connected to the rotor, and the generator can be directly tied to the grid [2] For small- and medium-size wind turbines, fixed-pitch or stall-regulated horizontal-axis wind turbine is one of the two common topologies in both research and industrial sectors, and the other one is pitch-controlled wind turbine [2].

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Methods

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Conclusion