Design and implementation of straight-bladed vertical axis wind turbine with collective pitch control

In order to improve the self-starting capacity of straight-bladed vertical axis wind turbine (SB-VAWT), a prototype with collective pitch control (CPC) was developed. The pitch angle of each blade was adjusted by a blade pitch control mechanism, consisting of four driving wheels attached to the blades and one servo motor, and motion of each blade was half of the rotor. Numerical simulations of SB-VAWT with flat profile were carried out to investigate the feasibility and effectiveness of the CPC method, and results show the peak of power coefficient of four-bladed prototype is more than 16% and the maximum power coefficient ranges from 0.5 to 0.7 for different rotor configuration with different blade number. Performance tests of prototype were implemented, and the results indicate that it is effective to improve self-starting capacity by utilizing the CPC mechanism; meanwhile the power coefficient of two-bladed configuration is a little larger than four-bladed rotor under the condition of same rotor solidity.